To solve the whole, removable / mobility vs performance issue, combined with the issue of backups and mirrors, this is what I'm doing now and it's really sweet:
I use an SSD for my audio projects in a removable tray. So, it's an "internal drive" with full 6gb bandwidth, but in a format that pops out. The cage for the tray fits in a standard 5.25" bay (i.e., where a DVD goes) and supports up to six trays! So, many libraries, or a RAID 0 for speed could be easily configured.
Here's the product: http://www.newegg.com/Product/Product.a ... 6817994147
Because it's removable, I can swap between machines (as long as they also have that 6 tray bay accessory).
It can even be used mobile with a cable that converts SATA III to USB3 and also powers it from another USB (the adapter uses two USB ports). Just pop it out and take it on the go. Best of both worlds.
Also, to solve the issue of backups / mirrors and project sharing / collaboration, a new app called BitTorrent Sync (for PC, Mac and Linux) is really solving all those problems well. It's like DropBox, only zero cloud. So, for those who don't want their studio on the internet, it's a brilliant solution.
Sidenote: Though the BitTorrent brand may seem "questionable," this is their pro-level product. As an IT professional myself, I would not use something that would be even slightly on the malware end of the spectrum. So, don't be put off by the "bittorrent" connotation. This thing is a lean, clean, enterprise-grade app that is easily configured to not so much as ping outside of the LAN -- fully self-contained. It can also be configured to sync a folder to another computer over the internet, but that is an optional feature and can be fully disabled. Anyway, they're clearly going after DropBox, Crashplan, etc. and working on their brand perception with this new app being an obvious key strategy to that end.
So, it's like DropBox only with no need for an internet connection, it all works cloud-less over a LAN. Since many studios need this requirement, I though I'd share this great new app (and it's free).
The one downside is that it's slightly CPU expensive. So those running a project at 95% utilization, might need to disable it while they're recording (a simple right-click in the tooltray [for PC] / menubar [for MAC]). Once you're done, just launch it again and let it run overnight, over lunch, etc. (just put it in your taskbar/launchbar for a one-click launch). Easy.
These two little tips are combining, in a synergistic way, to give me great options, mobility, performance and peace of mind. Just thought I'd share, as they're both slightly obscure, non-obvious and relatively new products. Very DAW-friendly solutions.
Rack-mounted DAW1 (Main): Cubase 7.5.10 64-bit, Win 8.1 64-bit, i7-4770K @ 4.0GHz OC, Stock Cooling, ASUS Maximus VI Gene Z87 mATX Motherboard, 16 Gigs DDR3, EVGA GTX 760, Focusrite Saffire Pro 40 on a Vantect FireWire 400 PCIe card (UGT-FW200), Two 30" ACDs
Rack-mounted DAW2 (Real-time Mastering Chain connected to DAW1 via ADAT Optical): Reaper 64-bit, Windows 7 Home Premium 64-bit, i5-4670K @ 4.0GHz, 16 Gigs DDR3, Focusrite Saffire Pro 40, One 20" ACD